Funding is requested for two Molecular Dynamics Storm 860 Imaging Systems, to be established as shared instrument resources within St. Jude Children's Research Hospital. These instruments will replace two existing Molecular Dynamics PhosphorImager Systems which are heavily used by a large number of NIH grant-funded investigators. The specific advantages of the Storm instruments over existing PhosphorImagers or alternative technologies include: (a) the ability to rapidly detect and quantitate direct fluorescence for analysis of nucleic acids or proteins in gels; (b) the ability to detect enzyme-amplified chemifluorescence for fast analysis of nucleic acids or proteins on membranes; and (c) the complete retention of storage phosphor autoradiograph, capabilities of existing PhosphorImagers that are routinely used at this institution. The fluorescence-based techniques benefit from stable reaction products, higher sensitivity than comparable technologies, linearity of signal detection over a broader range than competing technologies, freedom from exposures to film, use of existing labelling protocols, and quantification of results and digital storage of images for future reference. These capabilities can immediately enhance many research projects that currently use either chemiluminescence labelling of proteins or nucleic acids on membranes, or routine staining and visualization of nucleic acids or proteins in gels by transillumination and/or photography. These instruments will be regularly employed by a major users group of 36 NIH grant-supported investigators from 11 departments, and will facilitate the efficient progress of multiple research programs.